| Prefix | Factor | Fraction |
|---|---|---|
| centi | 10-2 | 1/100 (part per hundred) |
| milli | 10-3 | 1/1,000 (part per thousand) |
| micro | 10-6 | 1/1,000,000 (ppm, part per million) |
| nano | 10-9 | 1/1,000,000,000 (ppb, part per billion) |
| pico | 10-12 | 1/1,000,000,000,000 (ppt, part per trillion) |
| femto | 10-15 | 1/1,000,000,000,000,000 (ppq, part per quadrillion) |
| atto | 10-18 | 1/1,000,000,000,000,000,000 (part per quintiilion) |
